Electrical power systems may be used to electrically power automotive vehicles. Certain techniques for balancing storage cells of electrical power systems are known. As an example, U.S. Pat. No. 6,984,961 to Kadouchi et al. discloses a battery assembly system that includes a plurality of storage batteries connected in series, a voltage detector for detecting voltages generated in the storage batteries and a current detector for detecting a current flowing in the plurality of storage batteries. The battery assembly system also includes a state-of-charge (SoC) calculator for calculating the SoC of the storage batteries based on the detected voltages and current, and a charging/discharging unit for charging or discharging at least one of the plurality of storage batteries so as to equalize the SoC of the storage batteries calculated by the SoC calculator.
As another example, U.S. Pat. No. 6,882,129 to Boskovitch et al. discloses a battery pack for a battery-powered vehicle. The battery pack comprises battery modules coupled in series. The battery modules are configured to provide power to the battery-powered vehicle. Each of the battery modules has a SoC. The battery pack also comprises battery control modules (BCMs) that are coupled to the battery modules. Each of the battery modules is coupled to one of the BCMs and each of the BCMs is configured to monitor a battery module parameter. The battery pack further comprises a battery control interface module (BCIM) coupled to each of the BCMs. The BCIM is configured to receive the battery module parameter from each of the BCMs and independently adjust the SoC of each of the battery modules based on the battery module parameter.
As yet another example, U.S. Pat. No. 6,583,602 to Imai et al. discloses a lower battery block that feeds low-voltage power to a low-voltage load. At least one higher battery block is connected in series with the lower battery block and cooperates with the lower battery block to feed high-voltage power to a high-voltage load. The lower battery block and higher battery block each include cells. A DC/DC converter transmits power from the higher battery block to the lower battery block. A controller detects (i) an electric parameter of the lower battery block that relates to an average per-cell voltage in the lower battery block and (ii) an electric parameter of the higher battery block that relates to an average per-cell voltage in the higher battery block. The controller controls the DC/DC converter in response to the detected electric parameters to equalize the average per-cell voltage in the lower battery block and the average per-cell voltage in the higher battery block.